Primary electric cell or battery.



UNITED ,sTA'rrns PATENT OFFIE.

ALBRECHT HEIL, or FRANKFORT-ON-THErMAIN', GERMAN PRIMARY ELECTRIC CELLOR BATTERY.

No Drawing.

Specification of Letters Patent. Patented Nov; 39, 199%} Applicationflled April 6, 1909. Serial N0. 488,275.

To all whom it my concern:

Be it known that I, ALBRECHT HEIL, a subject of the German Emperor, andresident of Frankforton-the-Main, Germany, have invented certain new anduseful Improvements in Primary Electric Cells or Batteries, of which thefollowing is'aspecification.

It is aknown fact that cells, or batteries, for small hand lamps,driving fans, and other like purposes,whe're the cells, or batteries,have to be of small compass, rapidly decrease in activity, as the activesubstances contained in such cells or batteries can only be presentin'smallquantities, the depolarizer soon failing to act and the cell orbattery becoming inoperative.

The object of this invention is to provide a cell or battery, for suchpurposes which while containing but a small quantity of activesubstances, remains active for a long time and is uniform in its action.7

It is known that sulfate of mercury ossesses valuable properties as adepolarlzer ,(see for instance H aucics Die Galoanischeq Battem'en,1898, page 199, paragraph 3) but in practice the sulfuric acid' whichpasses into the electrolyte dissolves the zinc and forms hydrogen andcauses the sulfate of mercury itself to become dissolved without havinga depolarizing effect.

The decomposition of the sulfate of mercury occurs in a neutral solutionin such a manner that the salt is first decomposed into an easilysoluble acid salt, and then into a diflicultly soluble basic salt.Immediately an electrode of sulfate of mercury andcarbon, or graphite,is introduced into the elec-.

trolyte, the sulfate of mercury is decomposed, part of it passingdirectly into the solution and being consumed usel'essly at the zinc,and the remaining basic salt is decomposed when the cell, or battery,produces current,- so that on the one hand, sulfate containing an excessof mercury, or even metallic mercury, are formed, while on the otherhand, sulfuric acid and water are separated in the mass of carbon, orgraphite, so

that the basic salt becomes acid and dissolves I in the electrolyte,when the cell, or battery, is not at work, the acid solution attackingthe zinc without generating useful current.

For this reason the basic sulfate of mercury has proved unsuitable as adepolarizer for a durable and economical cell or battery.

In order to obviate the aforesaid disad- .acts in the nascent state.

vantage accordin to this invention there is added to the sulfate ofmercury (which is, as usual, mixed with finely divided carbon orgraphite) free mercuric oXid which combines with the liberated sulfuricacid and at the same time forms fresh sulfate of mercury as depolarizer,which possesses over that first introduced a greater activity, as itThere ,is thus obtained, a cell, or battery, producing a current ofremarkably constant intensity, with only a small amount of activesubstances.

Proportions which have been found suitable, but to Which I do not limitmyself, are

two parts by Weight of sulfate of mercury, and one part by weight ofmercuric oxid well mixed with one part by weight of graphite.

In selecting the electrolyte the chemical properties of the mercuroussulfate must be taken into consideration and an electrolyte containinchlorin should not be used, for the chlorin acting upon the sulfatewould produce a salt ofchlorin which would be etrimental to theoperation of the battery.

A suitable electrolyte is a solution of magnesium sulfate which whilethe cell, or battery, is not at work, is inactive toward thedepolarizer. The small conductivity of such a solution of magnesiumsulfate,

' which would impair the supply of current,

can be obviated by adding potassium sulfate to the solution. Potassiumsulfate alone is not suitable on account of the formation of a doublesalt on the zinc, but a mixture of both sulfates, in which the magnesiumsulfate predominates (say one hundred parts by weight of water, thirtyparts by weight of magnesium sulfate, and,

eight parts by weight of potassium sulfate) gives good results when usedwith the aforesaid depolarizer.

In an element of the hereinbefore described kind the current andelectromotive force will be considerably increased if manganese peroxidbe added to the depolarizmg mass consisting of graphite, sulfate of'mercury and mercuric oxid. By using a suitable mixture it is possibleto obtain a considerable reduction of resistance in the cell, orbattery, and an increase of the current intensity up to about sixty percent. Such a cell or battery will maintain a higher. voltage with auniform load, or the same potential with an increased load. Anotheradvantage is that a considerable portion of the comparatively expensivesulfate of mercury and mercuric oxid can be replaced by the cheap dioxidof manganese, the cell or battery having in this case longer activity.The addition of the dioxid of manganese can be varied within widelimits, but a good proportion for lighting on a small scale consists ofthree parts by weight of dioxid of manganese, two parts by weightofmercurous sulfate of mercury, one part by weight of mercuric oxid andone part by weight of graphite, but the cell or battery will .beeflicient if half of the combined wei ht of sulfate of mercury andmercuric oxid be replaced by dioxid of manganese without increasing theamount of graphite. In this, casean economy of fifty percentin mercurycompounds is obtained, 'while the total output of the cell or battery,is somewhat higher. The extra cost of the dioxidof manganese is so smallas to be practically negligible.

Having now fully described my said invention, what I claim and desire tosecure by Letters Patent, is

1. A primary cell of the kind described containing in combination withthe electrodes and the electrolyte of a depolarizer consisting ofsulfate of mercury, finely divided carbon and free mercuric oxid,substantially as and for the purpose set forth;

- 2. A primary cell of the kind described comprising in combination withthe electrodes and electrolyte a'de olarizer containing sulfate ofmercury, fine y divided carbon and free mercuric oxid, substantially asand for the purpose set forth.

' 3. A primary cell of the kind described comprising in combination withthe electrodes an electrolyte formed of sulfate of magnesium and sulfateof potassium and a depolarizer consisting of sulfate of mercury,

finely divided carbon and free mercuric oxid,

iubsltiantially as and for the purpose set ort ' magnesium and sulfateof 4. A primary cell of the kind described comprising in combinationwith the electrodes. an electrolyte formed of sulfate of otassium and adepolarizer containing sul ate of mercury, finely divided carbon andfree mercuric oxid substantially as and for the purpose set forth.

- '5. A primary cell of the kind described comprising in combinationwith the electrodes'and the electrol te of a de olarizer consistingofsulfate 0 mercury nely divided carbon, free mercuric oxid and peroxid ofmanganese, substantially as and for the purpose set forth.

6. A primary cell of the kind described comprising in combination withthe electrodes and electrolyte a depolarizer containing sulfate ofmercury, finely divided carbon, free mercuric oxid and peroxid ofmanganese, substantially as and for the purpose set forth.

7. A comprising in combination with. the electrodes an electrolyteformed of sulfate of magnesium and sulfate of otassium and a depolarizerconsisting of su' fate of mercury finely divided carbon, free mercuricoxid and eroxid of manganese, substantially as and or the purpose setforth.

8. A primary cell of the klnd described comprising in combination withthe electrodes an electrolyte formedgof sulfate of.

magnesium and sulfate of otassium and a depolarizer containing sul ateof mercury, finely divided carbon, free mercur c oxid and eroxid ofmanganese, substantially as and or the purpose set forth.

In testimony whereof I have hereunto set my hand in presence oftwowitnesses.

1 ALBRECHT I-IEIL. Witnesses JEAN GRUND, CARL GRUND.

primary cell of the kind described

